JPS63293311A - Screw fixing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw fixing device for fixing fixing materials or other objects to the surface of a hollow wall. Especially 1 usually looks like a diamond shape.

Formed by a 4') leg shaft which is fixed to the socket with an elastic web. A removable, reusable plastic screw fixing device that can be folded into a tongue shape that can be inserted into a drilled wall hole and then inserted into a socket through a fixing screw to be inserted later into the wall. It transforms into a triangular truss.

[Description of prior art]

Gypsum board sheet rock (shθetrock)''.

On hollow walls made of plywood or other relatively thin panel materials, clothes hangers are difficult to attach to horizontal bars, lighting fixtures, or other objects that are not strong enough to hold weight against the wall. Ordinary screws are difficult to fasten in such walls, so there is a need for some type of fastener to hold the screws in the wall to provide a strong and reliable fastener.

This kind of fixing device hits the inner surface of the hollow wall.

The screws are inserted so that they cannot be pulled out or twisted when tightened to attach the fixture to the wall.

An example of a conventionally used screw fixing device.

It consists of a metal sleeve with elongated grooves to form parallel lips between a flanged front socket and a rear socket that are inserted into a hole in the wall, and the sockets are threaded. In this device, a screw is inserted to engage the rear socket, and when the screw is turned, the lip deforms and opens into a bell-shaped configuration so that it is flush with the inner surface of the wall. The lip opening spreads the load over a large area of the wall around the perforation.

The main drawback of this type of metal screw fixation device is.

Once the lips are deformed and expanded, there is no convenient way to remove the fixation device from the wall. Therefore, in order to remove the screw fixing device, the flange of the front socket must be broken and the remainder of the fixing device must be pushed into the wall. This not only destroys the device and makes it impossible to reuse it, but also results in damage to the wall in order to remove the flange.

To overcome these deficiencies of conventional screw fixation devices, Kapnek U.S. Pat. The lip is fixed tightly to the inner surface of the wall using a spring. The fixation device is straightened and expanded by inserting the screw.

The fixing device can be pulled out through a hole in the wall. This type of fixation device can be removed and reused;
The relatively complex structure makes manufacturing and assembly expensive.

Dwyer U.S. Pat. No. 3,213.746.

A low cost screw fastening device molded from plastic is disclosed. The fixation device has a figure 7-shaped resilient web material that spreads apart to retain the fixation device socket in the wall when the screw is inserted. In this device, the teeth formed on the inclined surface of the web engage the inner surface of the wall in a narrow area around the hole, concentrating the load on that area rather than distributing it over a wide area. This load distribution is
This is important for relatively weak materials such as plasterboard, and if the fixing device is not dispersed, the heavy load placed on the fixing device will cause it to fall out of the hole.

Still other attempts include McSherry's U.S. Patent No. 3,
No. 651,734 has a screw socket inserted into a hole in the wall connected to a toggle lock. When folded, this toggle is placed into the hole. When expanded to a stable position around the center, the toggle is angled into the hole to actuate the lock. One major drawback is that once set, they are difficult to remove.

The most interesting prior art is applicant's U.S. Pat.
97.781 "screw anchor".

This patent discloses a removable and reusable screw anchor for attaching fixing members and other members to a hollow wall. The device has a diamond-shaped shaft with four legs, the front leg being connected to the front leg by a front tip hinge, the rear leg being connected to the front leg by a rear tip hinge, and the rear leg being connected to the front leg by a rear tip hinge. The end forms the rear tip. A rimmed socket whose hole coincides with the opening formed in the forward tip hinge is secured by a pair of elastic webs extending toward the rear legs of the shaft. The diamond-shaped shaft folds into a tongue-like shape that can be inserted into a hole in the wall to accommodate the socket.

The web then flips from its stretched state and resumes its diamond shape behind the wall.

When the self-tapping screw is screwed into the socket hole, the hole is threaded. When the screw advances beyond the hole, its tip touches the rear leg of the shaft and engages with it. This spreads the rear legs and gives the shaft a triangular truss shape. The bottom chord of the truss is formed by the rear legs and is pressed against the inner surface of the wall.

The truss will have a central post with a screw extending between the forward tip and the socket.

To remove the anchor from the hollow wall, simply pull the screw and the truss will collapse.

In the screw anchor disclosed in the above-mentioned patent, the ends of the rear legs, which form the rear tip of the generally diamond-shaped shaft, are unhinged and separate. The tip of the rear leg engages with the tip of the advancing screw, causing the diamond shape to deform and expand into a triangle. However, in reality, under certain circumstances, this deformation may not occur at all and the shaft may partially form a triangular shape.

This situation occurs when an operator drills into a hollow wall made of gypsum board or other relatively brittle material. If the drilling is not done carefully, the plaster around the hole on the inner wall surface will break or crumble. the result.

A ring-shaped bulge or 1 gypsum strip spread around the hole.

When the screw anchor is then inserted into this hole, the annular bulge on the periphery of the hole abuts the elastic web connecting the socket to the rear leg of the shank, so that the screw advances and spreads the rear leg. This creates resistance to the attempt to form a correct triangulation of the shaft.

Since the shape of the bulge is usually not constant but irregular, the amount of resistance that appears and how it is distributed varies depending on the hole.

In order to resist triangulation of the shank caused by the bulge surrounding the rear end of the hole drilled in the wall, the screw anchor of the above patent is designed so that the rear leg is attached to the rear side of the double chord of the shank. The end of the leg is an end with an inclined part, and three 'body states occur.

These ends are flexible and easily deform. Therefore,
When the rear leg of the shaft, whose tip is thought to be useful in forming a triangle, encounters resistance due to the bulge, the tip deforms and is no longer able to perform the required function.

In the first situation, where the rear leg encounters normal resistance to deformation, when the locking screw is inserted into the hole in the socket and rotated, the screw first deforms the flexibility of the rear leg of the shank. Proceed towards the end. The movement of the shaft is resisted by the bulge, and these tips enter between the screw threads and hit the root of the screw. Since the root diameter of the screw is smaller than the thread diameter, the extent to which the screw pushes against the rear leg and overcomes the resistance of the bulge is limited by the screw root diameter.

As a result, the shaft only partially forms a triangle,
The bottom chord presses against the inner surface of the wall and does not provide a triangular shape for maximum anchor retention.

Furthermore, for the screw to effectively enter the first situation, its length must be sufficient to span the inner surface of the wall and the forward tip of the partially triangular shank. This will form the central axis of the truss. The length of this screw must be longer than that required when forming a fully triangular shape, since the forward tip of the shank will approach the rear surface of the wall.

Besides the fact that long screws are required, which are costly, there is also the fact that in many cases the depth of the wall cavity is not sufficient to accommodate long screws.

A second situation that is sometimes encountered is that the tip of the posterior leg is deformed laterally by the advancing screw due to resistance to normal triangulation due to the bulge as the screw advances, resulting in Instead of pushing the legs axially, the entire screw pivots between the legs. As a result, the rear shaft portion of the wall retains its diamond shape and no triangular formation occurs in some areas.

Even if the screw is fully inserted into the socket.

The installed anchor remains without its full holding power.

In the second situation, even if the triangular truss is not formed to provide full holding power, a worker who cannot see behind the wall will not notice that the installation is incomplete.

The third situation represents the worst case possibility. Instead of the tapered tip penetrating between the threads as in the first situation or deforming laterally so that its sides become flat against the threads as in the second situation, Due to the uneven resistance caused by the peripheral bulge, one of the rear legs engages with the tip of the screw, making this leg triangular, while the other tip deforms laterally and does not fit into the screw. It becomes parallel to the opposite. As a result, one of the rear legs of the shank is somewhat displaced by its tip which later engages the root of the screw, while the other rear leg is laterally deformed.

As a result of the displacement, the shaft section takes on a distorted diamond shape.

Due to the distorted diamond, the holes in the forward tip will no longer line up with the holes in the socket, making it impossible to form a truss. This is because the tip of the advancing screw is one of the front legs.
It would probably hit.

This is because it will not fit into the tip hole on the front side. Again, even if the installation is incomplete, the worker will not notice it because he or she can see behind the wall.

Under normal conditions, the rear leg of the triangular shaft forms the chord of a triangular truss whose entire length is compressed against the inner surface of the wall, thereby distributing the load over a wide area. but,
In the situation of a raised circumference of the hole on the inner surface of the wall,
The center of the truss is pressed against this bulge, and the end of the truss furthest from the hole no longer touches the wall. This causes the load to be concentrated around the hole.

Due to the inherent brittleness of gypsum, this load concentration is undesirable. If the load becomes large, the anchor will break the plasterboard in the area of the hole, and the anchor will pull out of the wall due to the load. Thus, even if the triangles were successfully formed in the above-mentioned patent, perfect retention would not be achieved.

This does not mean that the anchors of the above patents are ineffective. Millions of them have already been successfully used, and the only problem is a build-up of plaster chips and other material around the holes, so one worker must be careful. If the quality of the drill used to form the hole is good, there will be minimal interference with the proper functioning of the screw anchor.

The main object of the invention is therefore to provide a molded or synthetic resin fixed installation which is removable from the wall in which it is installed.

More particularly, one object of the present invention is to provide a diamond-shaped shank with four legs, the rear leg of which is fixed by an elastic web to a socket having a hole, into which a screw is inserted. It is an object of the present invention to provide a screw fixing device which, when entering the front end of the shaft, engages with the rear end, separates the legs, and completely deforms the shaft into a triangular shape.

One of the salient features of this invention is that the required screws need not be longer than sufficient to reach the forward end of the triangular truss, but rather can be shorter than the screws of known screw fixation devices. .

Yet another object is to provide a screw fixing device in which the truss is immediately collapsed by removing the screws and the fixing device can be easily removed from the hollow wall without causing any damage to the wall.

Yet another object is to provide a plastic screw fastener that can support substantial loads of hollow wall earth and is inexpensive to manufacture.

[Means for solving problems]

The above object is achieved by a screw fastening device for attaching a fastening member to a hollow wall. The fixation device is a four-legged shaft, usually diamond-shaped, which can be pressed down, the front leg being connected by a front end hinge and the rear leg being connected by a lateral end hinge. It is connected to the front leg by the armrest. At the rear end of the shaft, the unconnected rear leg has the shape of a foot at its end, usually in the shape of an inverted V-shaped entrance.

A socket having a hole in it axially aligned with the hole in the front tip is secured on the outside of the nine feet by a pair of elastic webs extending towards each rear leg of the shaft.

To install the fixation device, its side hinges are pressed by hand to fold the shank into a tongue and insert it into a hole in the wall to accommodate the socket therein. The shaft is inside the wall and has regained its diamond shape. From there, a screw for holding the fixing member is inserted through the hole in the socket, and the screw is turned until the screw tip is expanded thereby and is blocked in the inlet for the screw. As the screw is being rotated and advanced, its head hits the bottom of the leg and spreads the leg, thereby giving the shank a triangular shape. At the end of the screw's entry, the screw tip is screwed into the hole at the front end, forming a triangular truss behind the wall, within which the screw becomes a central support. The rear legs are provided with load-distributing pads that abut against the inner surface of the wall to increase the retention of the truss when the truss is formed.

〔Example〕

1 and 2, one preferred embodiment of a screw fastening device according to the invention is shown, which fastening device is molded of e.g. polypropylene, nylon or other elastic synthetic resin material suitable to its structural characteristics. or manufactured n
Ru. The fixing device is the socket marked with the number 10 and the number 1
It consists of a compressible shaft section (shank) indicated by 1.

The front surface of the socket is provided with an annular flange 12 whose diameter is larger than the socket body. A socket was thus drilled into the hollow wall 14. When the diameter of the socket is large enough to fit into the hole 13 to enclose the socket, as shown in FIG. ing.

The socket 10 is provided with four sharp fins 15 spaced 90 degrees apart, creating bevel-cut edges that prevent the socket from being pushed into a hole in a plaster or similar wall. The socket bites into the plaster around the hole, stabilizing the socket in the hole and preventing its rotation. Socket 10 includes a vertical hole 16 adapted to receive a self-tapping screw as described below.

The shaft 11 is formed by a pair of front legs A and B which are hingedly connected to a pair of rear legs C and D. These legs have a diamond-like shape in the normal state of the shaft. The normal state refers to the state in which the product is shipped from the factory, that is, the state in which it is in the hands of an operator before it is installed. Leg A is connected to leg B by a forward end hinge If, which hinge Hf corresponds to the hole 16 in the socket 10. There are axially coincident openings 17. The front legs A and B are hinged, and the rear legs C and D have side hinges H.
It is connected to the town by Hs2. These three hinges are preferably integral with the plastic legs of the shaft.

The rear legs C and D are not connected, but they do not bend relatively.
There are thick legs F1 and F2, the flat bottoms of which form an inverted V-shaped inlet forming the rear end of the diamond-shaped shaft. This inlet is axially aligned with the bore 16 of the socket 10.

The socket 10 is connected to the shank 1 by a pair of outwardly extending elastic webs W1 and W2 which are integral with the rear legs C and D.
Attached to 1, it joins the free ends of C and D, which are shaped like n2 legs, at a point where they are out of place. The legs of the stem are hinged together so that the stem can be folded and pushed with a finger. As shown in Figure 3, press with your finger at the side end hinges H and H in the opposite direction of the arrow. As shown in Figure 4, the legs become flat and tongue-shaped, allowing the shaft to be inserted into the hole 16 drilled in the wall 14.

When the self-tapping screw 19 is screwed into the hole 16 of the socket 10 for fixing a bracket, fixing member or other object to the outer surface of the hollow wall 14, as shown in FIG. 16. Perform thread cutting. As the operator continues to turn the screw, the tip or end of the screw is blocked by the inverted V-shaped entrance defined by the flat bottoms of the feet F1 and F2.

The inlet is enlarged to allow entry of the screw. As you continue to turn the screw, the head of the screw will hit the bottom of the foot and work to spread the foot wider.

The diameter of the screw thread 19c is much larger than the diameter of the screw root 19H. The continuous spiral spacing of the threads of the screw is less than the vertical dimension of the bottom of the foot, and the bottom has at least two threads.
It straddles the threads, so it won't fall in between the threads. Therefore, when the screw passes through the inlet and the threads engage the bottoms of the feet F1 and F2, they are pulled apart, thereby deforming the diamond-shaped shaft into a triangular shape as shown in Figure yjfJ6.

This complete triangle occurs when the screw first enters between the bases of the feet and before the leading end of the screw has fully reached the forward end hinge HfK. Therefore, the length of the screw does not need to be longer than the distance between the base and the apex of the triangle. It goes without saying that the required length of the screw must take into account the thickness of the object 20 to be fixed by the fixing device.

As the screw continues to enter, its tip will enter hole 1 of the front end hinge Hf.
7 and thread to form a central post or beam extending between the forward end and the socket at the midpoint of the chord of the triangular truss. This string is formed by rear legs C and D which are pressed against the inner surface of the wall. This generates strong forces in the triangular truss, giving the screw fixation device exceptional holding power and allowing it to support heavy loads.

As already mentioned, in some cases, an annular mound of broken plaster fragments forms around the periphery of the hole on the inner surface of the wall.

This can be done as shown in FIGS. 5 and 6. This bulge impinges on the elastic webs W1 and W2 of the fastening device, which provides resistance to the deflection of the webs that occurs during the deformation of the shaft from a diamond shape to a triangular shape. However, since the legs F1 and F2 of the shaft are relatively unflexible and are separated by the advancing screw, the legs C and D on the rear side are able to apply a strong bending force to the web to resist the resistance caused by the bulge. Become. Therefore, the shank lies under the rear legs C and D, where the bulge extends outward in the area of the bulge around the hole, preventing these legs from fully abutting the inner surface of the wall. This results in the shape shown in Figure 6.

The disadvantageous effects resulting from the bulge 21 of the prior art fixation device disclosed in the aforementioned U.S. Pat. No. 4,197,781 are illustrated in FIG.

It can be seen that the fixation device has rear legs C and D with beveled tips T1 and T2. These tips fall between the threads 19C of the screw 19 and hit the root 19H of the screw, and as in the first situation described in the background section of the invention, when the tips fall off, the shank forms a partially triangular shape. Make it. And because of the bulge 21, the load is concentrated around the hole.

This is because this area is the only area where the chord of the truss is pressed against the inner surface of the wall, so the tip of the screw 19 is inserted into the front end hinge hole 1 (
Even if you enter F and pull this end toward the wall, a perfect triangular shape will not be formed.

In the present invention, bulges cause similar problems. to the rear leg to solve this problem.

Load distribution pads are provided adjacent to the lateral end hinges and integral with their feet and contacting the inner surface of the wall.

In this way, the load is distributed over the area around the hole.
, thereby increasing the load-bearing capacity of the fixing device.

The screw fixation device according to the invention is preferably manufactured by low cost injection molding techniques. For this purpose, it is preferable to use a mold in which the rear legs C and D are folded back in a winged manner, by means of which the webs W1 and W2 connecting the socket to the shaft are formed. Shows the opposite bend. In a separate step after shaping, the shaft is reshaped, creating a diamond shape with the web extending outward. This is the manufactured form of the screw fastening device and the form that is available to the operator.

Since the legs C and D are formed in this way, the webs W1 and W
2, the plastic memory required is reduced. As a result, the anchor shaft takes on a tongue shape for later insertion into the hole.
The web has a straight shape and its tongue is released when it passes through the hole.

The stem returns to its original diamond shape due to web memory.

Although preferred embodiments of the hollow wall screw fastening device according to the invention have been shown and described, many variations may be made without departing from the spirit thereof. Thus, although the fixation device has been described in the form of a self-tapping screw, in reality a conventional screw would be used in the threaded hole. And in practice the side hinges would be fragile, so the front leg of the shaft could be torn off and the rear leg used as the shaft of a screw fastening device to a solid wall, as described in that patent.

[Brief explanation of drawings]

FIG. 1 is a front perspective view of the screw fixing device of the present invention as seen in the direction of the socket. 2 is a rear perspective view of the screw fixing device of FIG. 1 taken away in the direction of the shaft; FIG. FIG. 6 is a state diagram illustrating how the fixation device is folded to enter the perforation in the hollow wall. FIG. 4 shows the folding fixation device inserted into the borehole. FIG. 5 shows a state in which the locking device has entered the borehole and the shank is diamond-shaped and is about to engage the inlet formed by the end of the rear leg of the shank; FIG. 6 is a diagram showing the state in which the fixing device is completely installed. FIG. 7 is an installation state diagram of a known screw fixing device for comparison. In the figure, 10... socket, 11... shank, 12... flange, 13, 16, 17... hole. 14...Hollow wall, 19...Screw, 19C...Screw thread. 22.23... Pad, A, B, (!, D... Leg +
F1+F2...Foot+Wl+"2...Web, Hf...Front end hinge. H8+++Hs2...Side end hinge procedural amendment (method) Showa/2nd year? month 2θ day

Claims (1)

[Claims] 1. A screw fastening device, usually diamond-shaped, compressible and cooperating with a screw, for holding a fastening member or other object on the outer surface of a hollow wall; A pair of front legs joined by a front end hinge having one hole, and a pair of rear legs joined to the front legs by a side hinge, and the ends of the rear legs. a shank with four legs, the shank being unjoined to form a rear end of the shank, the legs having a bottom generally defining an inverted V-shaped entrance; comprising a socket with a corresponding hole and a pair of normally stretched elastic webs fixing said socket to each rear leg of the shank at a point on the outside of the leg, said shank being When the side hinges are pressed by hand, the stem folds into a tongue shape, and the socket is inserted into the hole in the wall until it fits into it, and the stem turns behind the wall and assumes the shape of a diamond. The screw, which is returned and rotated and inserted into the socket hole, is advanced until its advance is blocked by the entrance that allows the expanded screw to enter at its tip, and the thread of the advancing screw engages with the bottom of the leg. to separate the rear legs, allowing the shank to assume a triangular shape, and as a result of screw entry, the tip of the screw is self-tapping received in the front end hole, and behind the wall the screw receives a triangular truss forming a central truss. A screw fixing device characterized by: 2. The fixation device of claim 1, wherein each of said bottom portions has a length sufficient to straddle adjacent threads of a screw. 3. The screw fixing device according to claim 1, wherein the fixing device is molded from synthetic resin and the hinge is a living hinge. 4. The rear leg has a pad on its outer surface at a position that causes the lateral hinge to bite into the inner surface of the wall when the truss is formed. Screw fixing device. 5. The screw has a length sufficient to reach the front end hinge when the shank is triangular.
Screw fixing device as described in section. 6. The screw fixing device according to claim 1, wherein the socket is provided with a fin that penetrates the wall of the hole to prevent the fixing device from rotating when the screw is rotated. 7. The screw fixing device according to claim 6, wherein the socket is provided with a flange that abuts the outer surface of the wall when the socket is seated within the borehole. 8. The screw fixing device according to claim 1, wherein the foot is relatively thick and has low flexibility. 9. Claim 1, characterized in that the legs are flat and parallel when they are engaged with the threads of the screw.
Screw fixing device as described in section. 10. The screw fixing device according to claim 1, wherein the screw is a self-tapping screw, and the socket hole is threaded thereby. 11. The screw fixing device of claim 1, wherein the socket is prethreaded to receive the screw.